The boys all crowded round the spot, and looked eagerly up, but they could not see any beam.
"You cannot see it," said the guide, "now, because you have just come out from the light of day. We shall come back this way pretty soon, and then you will be able to see it; for your eyes will then get accustomed a little to the darkness of the dungeon."
So the guide went on, and the boys followed him.
They next came into a very large apartment. The front side and the back side of it were both curved. The back side consisted of the living rock. The front side was formed of the outer castle wall, which was built on the rock at the very margin of the water. In the centre was a range of seven massive stone columns, placed there to support the arches on which rested the floor of the principal story of the castle above. The roof of this dungeon of course was vaulted, the arches and groins being carried over from this range of central pillars towards the wall in front, and towards the solid rock behind. All this you will plainly see represented in the engraving.
THE DUNGEON IN THE CASTLE OF CHILLON.
This great dungeon was lighted by means of very small loopholes cut in the wall, high up from the floor. The light from these windows, instead of coming down, and shining upon the floor, seemed to go up, and to lose itself in a faint attempt to illuminate the vaulted roof above. The reason was, that at the particular hour when the boys made their visit, the beams of the sun which shone directly from it in the sky were excluded, and only those that were reflected upward from the waters of the lake could come in.
The guide led the boys to one of the central pillars, and pointed to an iron ring which was built into the stone. He told them that there was the place where one prisoner was confined in the dungeon for six years. He was chained to that ring by a short chain, which enabled him only to walk to and fro a few steps each way about the pillar. These steps had worn a place in the rock.